Alisol A attenuates hypothalamic inflammation and metabolic dysfunction in high-fat diet mice

High-fat diet (HFD)-induced obesity, with emerging evidence for central nervous system involvement, is characterized by hypothalamic inflammation and metabolic disruption. Alisol A (AA), a triterpenoid from Alisma orientale, has anti-inflammatory and metabolic regulatory properties, but its effects on HFD-induced hypothalamic dysfunction have not been systematically characterized. Therefore, this study examined whether AA treatment during HFD exposure attenuated hypothalamic dysfunction.

Male mice were fed an HFD with or without AA. We assessed systemic metabolism, hypothalamic gliosis, cytokine levels in the hypothalamus and serum, neurometabolites by magnetic resonance spectroscopy, functional connectivity by resting-state functional magnetic resonance imaging, neuronal and synaptic ultrastructure by transmission electron microscopy, behavior, and hypothalamic bulk RNA sequencing with targeted quantitative real-time polymerase chain reaction validation.

AA limited HFD-induced weight gain and improved glucose tolerance, insulin sensitivity, and lipid profiles. Concomitantly, it partially corrected HFD-related hypothalamic neurometabolic alterations, reduced microglial and astrocytic activation, and lowered hypothalamic and serum pro-inflammatory cytokine levels. Moreover, AA attenuated neuronal and synaptic ultrastructural abnormalities, with partial rebalancing of HFD-related hypothalamic connectivity and improved learning and working memory performance in HFD-fed mice. Transcriptomic profiling identified AA-associated alterations in hypothalamic inflammatory and metabolic transcriptional programs, with quantitative real-time polymerase chain reaction validation of representative differentially expressed genes.

In HFD-fed mice, AA treatment was associated with improvements in systemic metabolism, inflammatory status, hypothalamic function, and learning and working-memory performance.